Berets are items obtained from Level 1 Treasure trails or by trading with other players. They provide no combat bonuses and are purely for show. They come in black, white and blue. Black berets can be attached to a Mime mask by talking to Patchy on Mos Le'Harmless for a price of 500 coins.
In June 2009, the White Beret's price saw an increase of around 200% when a glitch was fixed that was causing people to turn bald when they equipped the berets.
It seems that in Tutorial Island the RuneScape Guide was wearing a red beret (which doesn't exist in the game). Both of the Grand Exchange Tutors appear to be wearing berets as well.
The berets' examine text, "Parlez-vous Francais?", is French for "Do you speak French?"; in the French version, the text is changed to "Il ne manque plus que la baguette et le litre du vin" (The only thing missing is the baguette and the litre of wine). Referring to the stereotype of French people.
The Silk Merchant in Ardougne square also wears a Purple Beret (which doesn't exist in the game).
There is a gambler in the rat pits of Falador wearing a Pink Beret (which doesn't exist in the game).